For many years, the tool handle industry has used solid wood handles for tools such as sledge hammers, pick axes, and the like. More specifically, hickory wood is used because it is lightweight, resilient and extremely strong providing optimum physical characteristics for use in such implements. Many attempts have been made to find synthetic materials to provide a tool handle that is equal to or constitutes an improvement in physical characteristics obtained in using hickory wood for these handles. However, to date, none has been found.
The reinforced tool handle of U.S. Pat. No. 2,837,381 has the problem of twisting about the longitudinal axis of the handle during use of the striking instrument. The fiberglass reinforced tool handle of U.S. Pat. No. 2,940,492 is extremely heavy and does not dampen the shock to the same degree as the wood handle. The completely molded handle disclosed in U.S. Pat. No. 3,770,033 has also been found to be an unsatisfactory substitute for the wood handle.
The U.S. Pat. No. 3,712,659 discloses a wood handle having a coating of synthetic material on a core member. In this particular instance, the synthetic material is an epoxy resin coating. This coating is simply given to provide an insulating or impact cushioning hand portion and prevent exposure of weather to the wood core. The coating provides no additional strength characteristics to the wood core. The same is true of the wood core articles disclosed in U.S. Pat. No. 3,220,731. There, a particular application of a film of an amylose solution is applied before coating the wood core with a resinous composition.
The standard prior art pick handle consists of a single piece of wood that is about 36 inches along and elliptical in cross section. The dimensions of such handles are established by Government specifications and the elliptical cross sections vary according to their location along the handle.
The end on which the pick head is disposed flares outwardly from the stem of the handle to dimensions of 31/8 inches along the major axis and 21/8 inches along the minor axis. The pick head has an eye which also flares outwardly. The pick head implement is placed over the butt end of the handle and slipped over the flared end portion thereof. The pick head tool fits tightly because the tool holding end portion is flared in the same manner as the eye or opening of the tool itself. The head is wedged even more tightly on the handle as it is used because of the outward centrifugal force that is generated when the pick implement is swung.
According to the production methods of the prior art, a pick handle requires a blank of correct length which is tapered from dimensions of 31/2 inches 21/2 inches at the head to 2 inches by 2 inches at the butt end. Because the blank is too large to be kiln dried before it is turned to the desired dimensions, the handle is turned from a green piece of wood. The turned green handle is then kiln dried resulting in blanks which shrink in varying amounts. That is, the kiln dried green turned handles will not have a uniform size with a variance of up to about plus or minus 1/16 inch.
Using this process, one man can generally produce approximately 400 pick handle blanks per day. The pick handle blank has approximately 0.6 to 0.65 board feet of hickory after it has been turned in a wood lathe and finished. The rough cut blank from which this pick handle is cut has an initial size of approximately 2.0 board feet. Thus, there is a tremendous amount of waste associated with the prior art processing. The supply of hickory is limited because it is grown only on the North American continent.
As it has been recognized in industry, there is a long felt need for a tool handle having the strength and durability of wood without being severely limited by the supply of hickory which is particularly used in the striking or percussion implements such as pick axes. No one has directed any effort to reducing the amount of wood required in such a tool handle until the present invention.